Method of preparing printing-plates.



E. E. wovomvt METHOD OF PREPARING PRINTING PLATES.

' D DEC 13 191 1,288,657.. v Patented Dec.24,1918.

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EMIL E. NOVOTNY, RIVERSIDE, ILLINOIS, ASSIGNOR TO J. STOGDELL STOKES, OFMOORESTOWN, NEW JERSEY.

' underlay and overlay iIlCOlPOl'EItBCl in the plate;

METH OD 0F PREPARING PRINTING-PLATES:

To all whom it may concern Be it known that I, E1111. E. citizen of theUnited States, residing at Riverside, in the county of Cook and State ofIllinois, have invented certain new and useful Improvements in Methodsof Preparing Printing-Plates, of which the following is a specification.

This invention relates to an improved method of preparing printingplates having metallic printing surfaces, such as electrotypes,stereotypes, and etchings.

' As is known to those skilled in the printing art, the usual printingplate, prior to its use on the press, must undergo certain makereadytreatment inorder to insure proper results in the printing operation. Inpreparing the plate, therefore, it is the common practice for thepressman to resort to the use of underlay and overlay, but suchmake-ready does not of itself form an integralpart of the plate, that isto say, is not As contradistinguished from this ordinary practice Ipropose to prepare the printing plate by such NOVOTNY, a

a method, that the necessary or desired make-ready will be lncorporatedin the plateitself, thereby obviating the use of separate when the plateis in the press, as my improved plate when completed, will be ready forimmediate use, without additional treatment.

Another advantage 1ncident to so incorporating the make-ready in theplate itself,

as is done with my invention, is that I am enabled to use, in thepreparation of the plate, certain standard make-ready, applicable. tothe particular press upon which a plate is to be used and this standardmakeready may also be repeatedly employed for the preparation of as manyplates as desired. Of course in printing make-ready is required, notonly to compensate for errors such as those in the type body but alsofor errors. due to some peculiarity or defect of the particular press.It is therefore the practice for the pressman, on'practically every job,to prepare make-ready to compensate for this press defect. of sopreparing the make-ready each time is apparent when it is to beconsidered that paper or other material of a compressible nature is usedfor the make-ready and con scquently will, during the running of theSpecification of Letters Patent.

being no longer accurate. my lnvention I may use make-ready which onlyused to be taken.

The necessity.

Patented'Dec. 2d, 1918.

Application filed December 13, 1916. Serial No. 136,675.

press, be more or less affected by the pressure, so that finally it hasIn the practice of is standardized or permanently prepared for thesepress errors, and as such make-ready is temporarily in the preparationof the plate and is not usedupon the press itself, or during. theprinting operation, it may be employed in the preparation of otherplates.

In the accompanying drawings,

Figure 1 is a cross sectional view taken through a conventional form ofcasting box and showing a step in the production of the plate. 1 v

Fig. '2 is a cross sectional view taken through the plate and itsbacking after it has been removed from the casting box. I Fig. 3 is asimilar view of the plate itself after the phenolic backing has beenremoved therefrom and after the back of'the plate has beenshaved tofinal dimension,

Fig. 4- is a cross sectional view through a curved plate.

In practising the invention the ordinary metallic plate, made in theusual manner from a previously set type body or etching and whichplate-at this time is of greater thickness than will be finally desiredor required, is placed in a rigid proof press which is so constructed asto accuracy, that it will not of itself impart any errors to the proofThe proof taken on this press will, however, in all probability showcertain usual impressional errors due to the irregularities of theplate, and these must be compensated for-of course by the usualmake-ready, as must also certain errors which will be due to thepeculiarities of the particular press upon which the plate is to befinally used. Furthermore, it may be desired to employ make-ready toinsure such pressure as may be necessary toobtain a. particular kind ofprinting, such, for instance, as where it is desired to have one'part ofthe printing appear shaded or heavier than another portion.

The proof having, thus been taken, the usual corrections thereto aremade and-the proper amount of make-ready is determined upon,and saidmake-ready which is in the to be replaced as.

. section 7 of the castin box condensite,

then re-inked and the proof-re-taken, and this practice is continueduntil the print or prints produced from the plate reveal the characterof printing desired? The plate and the make-ready are now removed fromthe proof press and-such make-ready which formed overlay on the pressissecured to the back of the plate, preferably by pasting its edgesthereto and coincident with the type matter to be corrected. The face ofsuch plate is now cleaned,'and when dry, is coated with a weak solutionof soap and water which acts as a separating medium. The plate which isshown at l, is now placed withthe make-ready so positioned, asillustrated at 2, in a casting box 8. This casting box, asconventionally illustrated in the drawings, includes a bottom or bed 4,upon which are mounted bearers 5, which are arranged to constitute afour sided or rectangular frame, suitable vents 6 being provided for theescape of surplus material, as hereinafter described. The top of thecasting box is indicated at 7 stood that the casting box may be heatedin any manner desired. The plate 1 with the make-ready 2' properlypositioned and attached to the bottom thereof, as above mentioned, isplaced on the bed'of this casting box with the printing or type surfaceof the plate uppermost, and upon this printing or type surface is placedthe plastic material, preferably in the nature of a phenoliccondensation product of which there are several well known kinds, suchas or bakelite. This layer or sheet 8, if desired, is preferably heatedprior to placing it upon the plate 2 so that it is in a suitable plasticor soft condition when imposed upon the printing surface of the plate.ressure is now applie by lowering the top until it rests upon the topfaces of the bearers 5. to be noted that this phenolic product or'material shown at 8 even in its plastic condition has but a restrictedflow and is confined against undue diffusion or spreading by the frameformed by the bearers 5, and if the top 7 of the casting box be rapidlyclosed and pressed against the phenolic material 8, the surplus materialwill escape but slowl through the vents 6. the entire cubical areaformed by the top and bottom and bearers of the casting box will becompletely filled and the plastic or sluggish phenolic material beingunable to escape acts as a flexible ram against the metallic printingplate 1 forcing this plate downward so that themake-ready 2 will beactually embedded in the bottom of the plate 1 andthe entire bottomsurface of the plate will be brought against the bed of the casting box.Of course this forcing ofthe make-ready into the body of the plate 1will result in the and will push terial thereon and it is to be underalayer or sheet 8 of.

Now it is havin prepared The result will be that g to a flat level.

corresponding or complementary amount of the material so that themake-ready compensation will appear on the printing face of the plate.The casting box may now be permitted to cool and is then opened and theplate with the layer or body ofphenolic mais removed from the castingbox. The phenolic layer 8 at this time having assumed its set orhardened form may now be placed face downward ona suitable flat, rigidsupport such as the bed of a shaving machine, and as the bottom of themetallic printing plate 1 is now uppermost the .make-ready may beremoved or stripped therefrom, leavin irregularities in the back of thisplate 1. he bottom or non-printing face of the metallic plate 1 is nowshaved to the desired degree or extent so as to resent an absolutelyflat, smooth surface an When the phenolic layer is stripped from theprinting face, the metallic printing plate itself, which is now of theproper thickness and ready for use on the ress will appear as shown inFig. .3. It wil be noted in connection' with the material equivalent tothe make-ready employed has been caused to appear on the front of theface with the required regulari.

ties and irregularities, this taking place as above mentioned during thetreatment of the plate in the casting box. I might'herein mention thatin-connection with the making of the plate I may employ what may betermed standard make-ready;- Words, a particular press may have certainplate shown in Fig.3 that.

in other 7 structural defects therein which may have tobe provided forin practically every instance; and in order to embody this in the plateIf; would previously ascertain what make-ready would be necessary inthis connection, and such make-ready would at the time of treating theplate in the casting box place such standard make-ready on the bed ofthe casting box or beneath the plate and employ it as a part of thecomplete make-ready to which the plate was subjected during itspreparation. Then when the make-ready ,is-siibsequently stripped fromthe printing plate after the latter has been removed from the castingbox this standard make-ready could be laid aside and preserved and thenused in the preparation of subsequent plates. If it is desired toproduce a curved printing plate such as is shown at 9 in Fig. 4, thisform of plate being adapted for use in connection with the rotary press,I would proceed as above described for the making of the flat plate upto and including the operation of shaving the bottom of the'pla'te.However, instead of then immediately stripping the phenolic layer fromthe face of the flat plate, I would permit such layer to remain thereonand then subject both the metallic plate and its phenolic layer to theaction of sufficient heat to make the phenolic layer flexible and wouldthen subject the metallic plate with such flexible imposed backing layerto the action of a bending machine of any suitable typefor the purposeof curving or bending the metallic plate to the desired radius orcurvature. Inasmuch as the metallic plate under such circumstances issolidly backed up by the layer of phenolic material I insure thatuniformity of curvature throughout the entire area of the plate will beattained with practically no stretching of the printing plate becausethe bending or curving of the surface of the plate takes place in theneutral arc of the two bodies of material, or the plate andthe backing.Consequently, the printing face of the plate will not be distorted, Thephenolic backing layer may now be stripped and the curved plate shown inFig. 4 is the result.

WVhile I have herein shown and described a preferred manner ofpractising the invention, I wish it to be understood that I do not limitmyself to all the details herein set forth by way of illustration, asmodification and variation may be made without departingfrom the spiritof the invention or exceeding the scope of the appended claims.

What I claim is:

. 1. The herein described method of preparing a printing plate whichcomprises placing a predetermined amount of make-ready material againstthe back of the plate, imposing upon the face of the plate abody ofplastic material and subjecting said plastic material and'pl'ate topressure while in a confined space whereby the make-ready is.

embedded in the back ofthe plate, while material of the body of theplate complemen-.

plate and removing the plastic material from v the face thereof.

2. The herein described method of preparing a. printing plate whichcomprises placing a predetermined amount of make-ready material againstthe back of the plate, im-

posing upon the face of the plate a body of sluggish, flowing plasticmaterial and subjecting said plastic material and plate to pressurewhile in a confined space whereby the plastic material acts as a ram themakeready is embedded in the back of the plate while the material of thebody of the plate complementary to the make-ready employed is brought tothe face of the plate, permitting said plastic material to set whileunder pressure, then removing the embedded makeready from the' back ofthe plate and then removing the plastic material from the face of suchplate.

4. The herein described method of preparing a printing plate whichcomprises placing against the back of the plate a predetermined amountof make-ready material, in-

cluding make-ready material standardized to the errors of the press uponwhich the plate is to be used, imposing upon the face of the plate abody of plastic material and subjecting said plastic material and plateto pressure, and then removing the plastic ma terial and the make-readyfrom the plate.

5. The herein described method of preparing a metallic printing platewhich comprises placing a predetermined amount of makeready materialagainst one face of the plate, imposing upon the opposite face of theplate a body of plastic material, subjecting said plastic'materi'al andplate to pressure in a confied space, whereby the plaster acts as a ramcertain of the material of the plate is forced by the make-ready to theopposite surface from the make-ready, and then re-.

moving the make-ready, then shaving the back of theplate and thenremoving the plastic material from the plate.

In testimony whereof I affix my signature.

EMIL E. 'NOVOTNY.

